Discovery of a nebula associated with a high proper motion sdB star

Ortiz, R.; Bijarchian, F.; Guerrero, M. A.; Akhlaghi, M.; Serra-Ricart, M.
Referencia bibliográfica

Monthly Notices of the Royal Astronomical Society

Fecha de publicación:
7
2026
Número de autores
5
Número de autores del IAC
1
Número de citas
0
Número de citas referidas
0
Descripción
All B-type subdwarf stars (hereafter sdB) should have low flux of ionizing photons, making them incapable of producing a noticeable circumstellar photoionized shell. However, a few sdB stars have been associated with circumstellar nebulae, resembling in some cases a planetary nebula. These discoveries spark doubts about the nature of the physical processes behind the formation of the nebula. In this paper, we describe the newfound parabolic-shaped nebula associated with the high proper motion sdB star TYC 3315-1807-1. The apex of the H $\alpha$ nebula is situated ${\simeq} 0.5$ arcmin in the direction of the stellar proper motion. A wider parabolic-shaped nebula is also detected in WISE W1 infrared images at 3.4 $\mu$m, whereas GALEX images show extended far-UV emission around the star within the optical and mid-IR emissions. Like most other sdB stars with associated nebulae, TYC 3315-1807-1 moves at a high-speed (102 km s$^{-1}$) across the Galactic plane. The low luminosity of TYC 3315-1807-1 cannot provide its wind with the momentum necessary to form and keep a bow shock. The nebula around TYC 3315-1807-1 is rather suggested to be a Mach wave partially excited by shocks and photoionization or the encounter of the star with an over-density clump in the ISM.